Unity in diversity: Lessons from macaque societies

Abstract

The macaque radiation is as old as the hominin radiation, approximately 7 million years. After Homo, Macaca has the widest geographical range among primates, and both of these genera are present in tropical and temperate regions as well. Whereas the single extant representative of the genus Homo diverged through processes of cultural diversification, extant species of macaques emerged through processes of evolutionary diversification. Macaque societies are characterized by profound unity and great diversity, and can best be described as variations on the same theme. To understand macaque variation and adaptation, we must take into account the processes that insure the persistence of their societies across generations and environments.

A comparative network analysis of social style in macaques

“…This increases rank differences between nonrelatives and promotes coalitions between kin, generating social networks based on strong hierarchies. In contrast, a less-pronounced kin bias results in more coalitions involving nonrelatives, and dominance relationships are more balanced, with close bonds arising even between unrelated group members (Thierry 2007).…”

“…Whereas all macaque species show the same basic patterns of social organization, they display broad interspecific variation in their social style, and any evolutionary explanation must account for the covariation of behavioural traits from one species to another resulting from linkages between traits (Waal & Luttrell 1989;Thierry et al 2004;Thierry 2007). In species with strict dominance relationships, the risk of being bitten in a conflict is relatively high and the best tactic for targets of aggression is either to submit or to flee rather than to retaliate, which impairs the occurrence of affiliative interactions between previous opponents.…”

“…In this case, affiliative interactions can arise more easily between opponents. Aggression intensity, dominance asymmetry and affiliation rates after conflicts can therefore be considered to belong to the same system of interrelated traits (Petit et al 1997;Thierry 2007). The occurrence of coalitions most probably creates a positive feedback loop between levels of dominance asymmetry and nepotism.…”

“…Social styles can be classified as 'despotic' and 'egalitarian' (Waal & Luttrell 1989;Matsumura 1999;Hemelrijk 2000), and macaque styles have been more accurately ranked on a 4-grade scale from less to more tolerant species (Thierry et al 2000;Thierry 2007). This scale is mainly based on patterns of agonistic and affiliative interactions.…”

Collective arousal when reuniting after temporary separation in Tonkean macaques

“…At this stage, however, we can only ask whether such emotional states have arisen independently through the evolutionary process as an outcome of certain kinds of sociality, or whether such mechanisms are the same in primates and elephants for instance, thus arguing for mammalian homology and raising the question of why they have not been reported in more taxa. The occurrence of collective arousals in Tonkean macaques may be promoted by the remarkably tolerant social relationships and the numerous conciliatory contacts which characterize them Thierry, 2007. Some macaque species display similar behaviors, and there are hints that they also display collective arousals (Sulawesi macaques: Thierry et al, 2000;stumptailed macaques: de Waal, 1996).…”